A reactor at the Ikata nuclear power plant in Ehime Prefecture, western Japan, has gone back online after being suspended for about one year.
The No.3 reactor restarted on Saturday. Workers in the central control room removed the control rods that suppress nuclear fission at 30 minutes past midnight.
Shikoku Electric Power Company shut down the reactor last October for regular inspections. It was kept offline by an injunction issued 2 months later by the Hiroshima High Court.
The ruling was revoked last month by another judge at the High Court, paving the way for a restart.
Shikoku Electric says if the process goes smoothly, the Ikata reactor will likely reach criticality -- a self-sustaining nuclear reaction -- on Saturday night.
It is expected to begin power generation and transmission on Tuesday, and start commercial operations on November 28th.
Ikata Mayor Kiyohiko Takakado in a statement called on Shikoku Electric to continue pursuing safety and reliability at the plant, and provide highly transparent information disclosure.
Members of a civic group opposing the nuclear plant on Saturday staged a demonstration at the site. One participant said she has heard nuclear reactors are needed to ensure stable energy supplies, but she finds it problematic life-threatening radioactive materials are being used to generate power.